Broad-band linear polarization in late-type active dwarfs

TL;DR

This study measures wavelength-dependent linear polarization in magnetically active late-type dwarfs, revealing polarization mainly due to magnetic effects and scattering, with correlations to activity indicators varying across bands.

Contribution

It provides new polarimetric data across multiple bands and analyzes the relationship between polarization and stellar activity parameters in late-type dwarfs.

Findings

Polarization decreases with wavelength from B to I band.

Major polarization sources are magnetic intensification and scattering.

Stronger correlations between polarization and activity indicators in B band.

Abstract

We present recent polarimetric results of magnetically active late-type dwarfs. The polarization in these stars is found to be wavelength dependent, decreasing towards the longer wavelength. The average values of degree of polarization in these active dwarfs are found to be 0.16+/-0.01, 0.080+/-0.006, 0.056+/-0.004 and 0.042+/-0.003 per cent in B, V, R, and I bands, respectively. Present results indicate that polarization in the majority of active dwarfs are primarily due to sum of the polarization by magnetic intensification and scattering. However, supplementary sources of the polarization are also found to be present in some active stars. The correlations between the degree of polarization and various activity parameters like Rossby number, chromospheric activity indicator and coronal activity indicator are found to be stronger in B band and weaker in I band.